The integrated forms of caprine arthritis-encephalitis virus (CAEV) and of equine infectious anemia virus (EIAV) were cloned in the L47.1 strain of bacteriophage Lambda. The restriction enzyme map of CAEV was determined and oriented relative to the viral RNA. The size of the long terminal repeats of CAEV is approximately 500 base pairs. The determination of the genetic relatedness of CAEV to other retroviruses as well as the molecular characterization of the cloned EIAV are now in progress.